Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C309/00—Sulfonic acids; Halides, esters, or anhydrides thereof
  • C07C309/01—Sulfonic acids
  • C07C309/02—Sulfonic acids having sulfo groups bound to acyclic carbon atoms
  • C07C309/03—Sulfonic acids having sulfo groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton
  • C07C309/13—Sulfonic acids having sulfo groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton containing nitrogen atoms, not being part of nitro or nitroso groups, bound to the carbon skeleton
  • C07C309/14—Sulfonic acids having sulfo groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton containing nitrogen atoms, not being part of nitro or nitroso groups, bound to the carbon skeleton containing amino groups bound to the carbon skeleton
  • C07C309/15—Sulfonic acids having sulfo groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton containing nitrogen atoms, not being part of nitro or nitroso groups, bound to the carbon skeleton containing amino groups bound to the carbon skeleton the nitrogen atom of at least one of the amino groups being part of any of the groups, X being a hetero atom, Y being any atom

Definitions

• This invention is directed to the acylation of aminosulfonic acids in which the neutralization and acylation of the acid is conducted in the solid phase.
• Non-gas phase bimolecular reactions generally do not readily occur unless conducted in the condensed phase, e.g. in a solvent or in the molten state.
• This condition is generally essential for the requisite intimate physical and chemical interactions of the reactants.
• two discrete, sequential chemical reactions occur in the solid phase, i.e. (1) the neutralization step of the sulfonic acid moiety with a base and (2) the subsequent amine acylation, to produce a superior acyl-aminosulfonic acid at a reduced cost. Both essential chemical steps occur virtually quantitatively in the solid phase.
• This invention is directed to acylating aminosulfonic acids, in particular the acetylation of aminosulfonic acids with acetic anhydride.
• the invention has substantial advantages over prior art methods because the prior art involves doing the acylation usually in the homogeneous phase in a solvent, typically water.
• German patent Nos.69555, 75084 and 116922 describe acetylations in acetic acid with sodium acetate as base while Kloetzel et al (J.Org. Chem., 26, 607) describe the use of acetic acid as solvent with pyridine as base.
• a number of works have utilized pyridine as solvent and base for the acetylation of aminosulfonic acids with acetic anhydride (A. Barco et al, Synthesis, 877 (1974); Forster et al, J. Soc.Chem.
• the present invention eliminates the solvent, salting out, filtration, and drying operation, and thereby substantially increases the process yield at a reduced cost. Importantly, in this age of environmental concern virtually all discharge of waste water or other liquid wastes is eliminated.
• the present invention directly produces a dry product in high purity and in very nearly quantitative yield. Furthermore, the process described herein is faster, more efficient and has higher space-time yields than prior technology.
• This invention is that of a new process of acylating aminosulfonic acids of the structure:
• A is a substituted or unsubstituted aliphatic, aromatic or heteroaromatic group, to produce the corresponding N-acyl derivatives or sulfonic acid salts thereof as the products of said process.
• the invention is a method of producing the N-acyl derivatives in the solid, semi-solid, or dough-like state, in the absence of any added solvent or other vehicle to facilitate the reaction.
• the proces is applicable to aminosulfonic acids and is especially useful in the production of acetylated amino aryl sulfonic acids, a number of which are important dyestuff precursors.
• the reaction mass consists only of the reactants, i.e., the starting dry or nearly dry aminosulfonic acid, the acylating agent, and some organic or inorganic compound capable of neutralizing the sulfonic acid moiety, because little or no acylation of the amino group occurs if it is not neutralized.
• Suitable neutralizing compounds or bases include the alkali or other metal carboxylates, carbonates, hydroxides, alkoxides or similar oxygen bases as well as nitrogeneous bases such as ammonia and amines.
• Preferred neutralization agents include hydroxides, acetates and carbonates of the alkali and alkaline earth metals. Most preferred are the hydroxides, acetates and carbonates of sodium, potassium, lithium and calcium.
• acylating agents include the carboxylic acid anhydrides, such as acetic and propionic anhydrides, and other similar reactive acylating agents, such as diketene.
• This invention is that of a process of acylating aminosulfonic acids.
• An aminosulfonic acid has the general formula, HO 3 S-A-NH 2' , where A is a substituted or unsubstituted aliphatic, aromatic or heteroaromatic group.
• Typical acids include:
• the moiety A includes alkyl, arylalkyl, substituted and unsubstituted phenyl, naphthyl and heteroaromatic groups which may contain substitutes such as a halogen, hydroxyl, alkyl, alkoxy, sulfo, nitro acylamino or mixtures of such groups.
• the reaction is conducted by mixing the reactants in equipment having the capability required for the mixing of moist or dry solids or otherwise viscous, heavy, or tacky materials which may pass through a plastic, or dough-like state. Examples of such suitable apparatus are double arm kneader (continuous or batch), ribbon blender, pan dryer, Venuleth, rotary or similar turbulent drying equipment.
• the physical state of the reaction mass during the course of the reaction is dependent on the choice of starting materials and reaction time, and can be a more or less free flowing powder, moist solid, or a dough-like mass or a combination of these states.
• the starting material and a molar excess of base in the range of about 0 to 100% excess, preferably about 5% excess are pre-mixed in the reactor, e.g., a kneader, and then treated in a controlled manner with a molar excess of acylating agent in the range of 0 to 100%, preferably 25-50%, most preferred about 50% excess.
• the reaction temperature is usually not a critical parameter and the reaction is usually done without external temperature control but such control may be applied where necessary.
• the reaction may be readily completed in the temperature range from about ambient to about 100° C., preferably from about 30° to about 80° and most preferably from about 30° to about 80° C.
• the reaction is typically accompanied by a moderate, brief exotherm which peaks at about 40°-50° C. and is rapid, being generally kinetically complete in less than an hour.
• the reactants will form a dough-like mass during or shortly after the addition of acylating agent which may start to revert back to a solid powder form towards the end of the reaction.
• the formation of the reaction product's powdery form can be facilitated by removing the volatile material (e.g.
• Broenners acid (2-naphthylamino-6-sulfonic acid) in an amount of 40 parts is charged into a double-arm kneader with a sigma blade configuration having a capacity of 150 cc, followed by 15 parts of 50% sodium hydroxide with mixing. After mixing for 10-15 minutes, 27 parts of acetic anhydride is added over about five minutes. The reaction mixture forms a soft dough-like mass and the temperature reaches a maximum of about 40°-45° C. within 10-15 minutes. After about 30 minutes the reaction mass is heated externally with steam under reduced pressure to remove water, acetic acid, and excess acetic anhydride.
• Metanilic acid (3-aminobenzenesulfonic acid) in an amount of 37.5 parts, and 18.7 parts of sodium acetate are charged into the kneader and the procedure described and 32 parts of acetic anhydride are added to the reaction mixture.
• the powdery reaction mass is mixed for one hour and then dried at 85° C. in a stream of air to give a 95% yield of 3-acetylaminobenzenesulfonic acid sodium salt.
• Liquid chromatography and titration analysis indicated a purity of greater than 97% and the presence of about 0.5% metanilic acid.
• Metanilic Acid in an amount of 37.5 parts and 9.1 parts of sodium hydroxide beads are mixed in a kneader for about 30 minutes and then 32 parts of acetic anhydride are added over a period of 7-8 minutes. During the anhydride addition, the reaction mixture forms a soft dough-like mass. After about one-half hour, the dough-like mass (temperature ca.40° C.) starts to revert to a moist solid. After one hour, external steam heating is applied and the mixture held under vacuum. After 1.5 hours the dry powder is discharged to yield 50.9 parts of white powder, 97.9% pure acet-metanilic acid sodium salt containing 0.1% metanilic acid (96.9% of the theoretical yield).
• H-Acid (8-Amino-1-naphthol-3,6-disulfonic acid), 87.6% as the monosodium salt and containing 10.6% water of hydration, were charged into a kneader in the amount of 60 parts, followed by the addition of 15 parts of sodium acetate. After the solids were mixed for a brief period, 24 parts of acetic anhydride were added gradually with continued mixing. When the addition was complete the reactants were heated by passing steam at a temperature of about 100° C. through the jacket of the kneader for about 1 hr. The kneading mass was then dried by continued heating in a stream of air.
• acylated aminosulfonic acids are so water soluble that they cannot readily be salted out with inorganic salts and are inconvenient and difficult to isolate.
• the product can only be precipitated from aqueous solution by acidifying to below pH 1 with a strong mineral acid such as hydrochloric acid.
• This particular technique is undesirable relative to the present invention for two additional reasons. The first is that such products present special safety and handling difficulties due to the fact that they are highly acidic.
• the 2-acetamino-6-naphthalenesulfonic acid via the solid phase technique is converted to the sulfochloride consistently in 8-9% higher yield (95% vs. 86% of theory) than the product via the aqueous ammonium sulfate salting out technique.
• Similar results are obtained with the conversions of 2-acetamino-8-naphthalenesulfonic acid salts to the sulfochloride.
• the solid phase technique has the additional and unexpected advantage of allowing certain products which were previously best isolated from water as their ammonium salts to now be optimally isolated as their sodium salts and thereby allow higher yields in their subsequent conversion to the sulfochlorides.
• the solid phase reaction thus allows one to use whichever neutralizing agent (base) he desires without taking into consideration subsequent processing parameters of the neutralized acyl-aminosulfonic acid.
• the increased yield afforded in the subsequent processing steps can be significant in these relatively high cost chemicals.
• the present invention by eliminating the solvent, eliminates the salting out, filtration and subsequent drying steps, and thereby also eliminates yield losses and, importantly, virtually all discharge of waste water. Not only are large waste water discharges eliminated, but also the solid phase technique readily allows the recovery of the volatile organic by-product from the acylation by simple methods. For example, in the case of acetic anhydride as the acylating agent, the valuable by-product acetic acid can be recovered and reclaimed nearly quantitatively simply by condensing its vapors during the drying operation. Such a recovery is not feasible in aqueous acetylations (or other acylations), and all the by-product acetic acid must be discarded in the waste water.
• the present invention directly produces a dry product in high purity and in nearly quantitative yield. Furthermore, the process described herein is faster and has higher space-time yields than the existing technology, and provides a very simple and general method which is universally applicable to all aminosulfonic acids and gives products in the most suitable physical and chemical form for subsequent chemical conversions.

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• 1985
  • 1985-04-24 US US06/725,068 patent/US4749523A/en not_active Expired - Fee Related
  • 1985-06-22 DE DE8585107751T patent/DE3561812D1/de not_active Expired
  • 1985-06-22 EP EP85107751A patent/EP0168680B1/de not_active Expired
  • 1985-06-28 JP JP60140670A patent/JPS6176454A/ja active Granted

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